Study of the effects of carbonaceous additives and metal oxides on negative plates of lead-acid batteries

Lead-acid batteries have been a dominant technology in large-scale energy storage systems since their invention in 1859. They continue to be the most commercially successful aqueous electrochemical storage system to date, playing a pivotal role in the development of modern electricity-powered society. Despite significant advancements in battery technology, lead-acid systems maintain their strong presence in the global market due to their simple design, low cost, ease of fabrication, wide availability, and well-established recycling processes. However, certain challenges persist, particularly the issue of sulfation at the negative lead electrode due to water loss, which limits their performance in heavy-duty applications. The incorporation of carbon materials—such as activated carbons, carbon nanotubes, graphite, and other carbon allotropes—into the negative active material (NAM) has shown considerable improvements in battery performance. Carbon additives enhance the cycling stability of lead-acid batteries, especially in conditions such as deep discharge, partial state-of-charge, and high-rate partial state-of-charge cycling. In addition, metal oxides like silica have been found to improve the performance of lead-acid batteries by altering key properties of the NAM, such as surface area and mechanical strength. This study investigates the combined use of carbon additives and metal oxides (including silica, ceria, and zirconia) to enhance the surface area and wettability of the NAM. These additives are synthesized and characterized to assess key parameters such as conductivity and surface area using techniques like thermogravimetric analysis (TGA), elemental analysis, contact angle measurements, conductivity testing, Brunauer–Emmett–Teller (BET) surface area analysis, Scanning Electron Microscopy (SEM), Raman spectroscopy, and X-ray Diffraction (XRD). The additives are then incorporated into the NAM, supported on a lead grid, and formed in a 2 V prototype cell. Electrochemical characterizations—including Electrochemical Impedance Spectroscopy (EIS), Linear Sweep Cyclic voltammetry (LSC), charge-discharge cycling, and water loss evaluation—are performed to measure the performance of the 2 V flooded lead-acid battery prototypes. Finally, post-mortem analysis of the negative electrodes is conducted using SEM, Energy-Dispersive X-ray Spectroscopy (EDX), XRD, and Raman spectroscopy to examine the surface morphology and degree of sulfation.